But blinding US early-warning satellites would not simply undermine its ability to spot conventionally armed missiles.

It would also compromise the ability of the US to detect nuclear-armed ballistic missiles and could raise fears that Russia was planning a nuclear attack on the US.

Indeed, the latest US Nuclear Posture Review - the key official statement of US nuclear policy - explicitly threatens to consider the use of nuclear weapons against any state that attacks its nuclear command-and-control systems.

This threat applies whether or not that state has used nuclear weapons first.